Most colorectal cancers arise from adenomatous polyps, and a large proportion of adenoma patients will develop new adenomas after their initial polypectomy. There is considerable controversy regarding an appropriate surveillance interval for adenoma patients following the removal of their initial adenomas. Therefore, studies assessing predictors for recurrent adenoma, particularly among patients with multiple or pathologically advanced adenoma(s), will provide valuable information for designing individualized, cost-effective surveillance and chemoprevention strategies for adenoma patients. Some tumor markers (genetic or epigenetic alternations) involved in the formation of colorectal neoplasms are promising predictors for recurrent adenomas, as they are believed to reflect a field cancerization process or a genetic predisposition to colon adenomas. We hypothesize that patients whose initial adenomas have certain altered genetic or epigenetic profiles may have an elevated risk of adenoma recurrence, and these tumor markers, along with pathologic features of initial adenomas can be used to predict the risk of adenoma recurrence. To evaluate these hypotheses we propose in this application a series of investigations, consisting of both hypothesis-testing and hypothesis-generating components as described below. For the reasons described in section BI, the major focus of this application will be on the study of predictors for recurrent adenomas among patients with multiple or pathologically advanced adenoma(s).